from sage.all import *
from Crypto.Util.number import long_to_bytes

n = 2 ** 512
m = 391190709124527428959489662565274039318305952172936859403855079581402770986890308469084735451207885386318986881041563704825943945069343345307381099559075
c = 6665851394203214245856789450723658632520816791621796775909766895233000234023642878786025644953797995373211308485605397024123180085924117610802485972584499
flag = long_to_bytes(discrete_log(c,mod(m,n))).decode()
print(flag) # flag{5f95ca93-1594-762d-ed0b-a9139692cb4a}